Antisense oligonucleotides AS-ODN

K4. Konopleva, M., Tari, A., Lopez-Berestein, A., and Andreeff, M., Inhibition of Bcl-2 with liposomal-derived antisense oligonucleotides (AS-ODN) induces apoptosis and increases the sensitivity of primary acute myeloid leukemia (AML) cells and cell lines to cytosine arabi-noside and doxorubicin. Blood 90 (suppl. 1), 10494a (1997). 

FICURE 1-1. Intracerebral infusion of antisense oligonucleotides (AS-ODN) that were targeted to the cloned CRH, and CRH2 receptor mRNA prevent translation into the receptor protein. Only a knock-down of the CRH, receptor, but not of the CRH2 receptor, reduces anxiety-related behavior in rats that were exposed to the elevated plus-maze test after central corticotropin-releasing hormone (CRH) administration. P <. 05, P <. 01. 

Abbreviations Ad-beta gal, beta-galactosidase AS-ODN, antisense oligonucleotides EC, endothelial cell EEC, endothelial progenitor cell NA, not available ... 

Dendrimers have been successfully used as a delivery system for antisense oligonucleotides (ODNs). ° "" Hughes et al. " reported the significant enhancement of the effectiveness of antisense ODNs in the presence of non-toxic concentrations of G5 PAMAM dendrimer. Bielinska et al. " reported the enhanced activity of antisense ODNs and antisense cDNA plasmids in the presence of PAMAM dendrimers in an in vitro cell culture system. Dendrimer was believed to enhance the transfer of ODN into cells. The electrostatic binding of the phosphodiester ODNs to dendrimers also extended their intracellular survival. Dendrimers at concentrations required to be effective ODN carriers were reported to be non-cytotoxic. 

In addition to pDNA delivery, the development of in vivo carrier systems for a new class of nucleic acid medicines such as antisense oligonucleotides (ODN) and small interfering RNA (siRNA), which can repress or silence the gene expression in a sequence-specific manner, is strongly desired. Recently,... 

As phosphorothioate oligonucleotides are widely used as antisense agents, there have been a number of reports on their mode of action. Using Rp and Sp phosphorothioate internucleotide linkages in ODNs, it was shown that Serratia marcescens endonuclease hydrolyses the Rp phosphorothioate bond with inversion of configuration at phosphorus. The presence of an Sp phosphorothioate... 

To aid hepato-cellular uptake of antisense ODNs, the phosphoramidites of cholic and taurocholic acids were prepared and added to the 5 -end of antisense oligomers." The oligonucleotides were further modified by the inclusion of phosphorothioate and benzylphosphonate internucleotide linkages. The bile acid conjugated oligomers exhibited enhanced lipophilicity as determined by HPLC, and when incorporated into duplexes no destabilisation was observed. An antisense phosphorothioate ODN targeted to the HIV-1 gag-mKNA was... 

The primary application of LNA has been in antisense therapy due to the aforementioned properties. It has been used to knock down human protein kinase C-a (PKC-ot) with greater efficiency than the corresponding phosphor-othioate ODN, as an inhibitor of human telomerase, to block the synthesis of RNA polymerase II and to inhibit human vascular smooth muscle cell growth. LNA-modified oligonucleotides have also been used in RNA interference (RNAi). ... 

The use of methylphosphonates (12) as antisense compounds has been reviewed by several authors [83,84]. Very good nuclease resistance and a different mechanism of membrane penetration are the most remarkable features of this ODN modification [85]. The lack of anionic charge however renders the compounds relatively insoluble in water. Drug/target duplexes do not activate RNase-H. Therefore, high concentrations of up to 100 pM are required to achieve antisense activity. Nevertheless, methylphosphonates seem to be suited elements of chimeric oligonucleotides. 

Block-graft copolymers synthesized by covalent conjugation of Pluronic and branched PEI were used as materials for preparation of polyplexes. Such polyplexes usually contain three components (i) DNA (ii) Pluronic-PEI conjugate and (iii) free Pluronic (Fig. 7). The formulations were prepared with both plasmid DNA and oligonucleotides (ODN), resulting in stable polyplex dispersion with the particle size in the ranges of 100—200 nm. These polyplexes were used successfully for delivery of plasmid DNA and antisense ODN in vitro... 

---